Erorr in create Package Body - oracle

Question

I Created Table called Class then its Package called PKG_Class also created
it is OK.
But the execution of (Backage Body) give me erorr "Package Body Created with Compilation Erorr"
create table Class
(
Class_id number(10) primary key,
Tybe number(5),
Class_name varchar2(10),
Max number(20)
);
CREATE OR REPLACE PACKAGE PKG_Class IS
PROCEDURE ClassAdd(
ID_C in Class.Class_id%Type ,
C_Type in Class.Tybe%Type ,
C_Name in Class.Class_name%Type ,
C_Max in Class.Max%Type );
PROCEDURE ClassUpdate(
ID_C in Class.Class_id%Type ,
C_Type in Class.Tybe%Type ,
C_Name in Class.Class_name%Type ,
C_Max in Class.Max%Type );
PROCEDURE ClassDelete(
ID_C in Class.Class_id%Type );
PROCEDURE ClassFind(
ID_C in Class.Class_id%Type ,
C_Type out Class.Tybe%Type ,
C_Name out Class.Class_name%Type ,
C_Max out Class.Max%Type );
FUNCTION FindClass(
ID_C in Class.Class_id%Type
) RETURN Class%ROWTYPE ;
FUNCTION Find(
ID_C in Class.Class_id%Type ,
C_Type out Class.Tybe%Type ,
C_Name out Class.Class_name%Type ,
C_Max out Class.Max%Type
) RETURN BOOLEAN;
END PKG_Class;
////////////////////////////////
CREATE OR REPLACE PACKAGE Body PKG_Class IS
PROCEDURE ClassAdd(
ID_C in Class.Class_id%Type ,
C_Type in Class.Tybe%Type ,
C_Name in Class.Class_name%Type ,
C_Max in Class.Max%Type )
IS
BEGIN
insert into Class
values(ID_C, C_Type, C_Name, C_Max );
Commit;
END ClassAdd;
PROCEDURE ClassUpdate(
ID_C in Class.Class_id%Type ,
C_Type in Class.Tybe%Type ,
C_Name in Class.Class_name%Type ,
C_Max in Class.Max%Type )
IS
BEGIN
Update Class set C_Type = Tybe ,
C_Name = Class_name ,
Width_Pool = Width_P ,
C_Max = Max
WHERE ID_C = Class_id ;
Commit;
END ClassUpdate;
PROCEDURE ClassDelete(
ID_C in Class.Class_id%Type )
IS
BEGIN
DELETE FROM Class WHERE
ID_C = Class_id;
Commit;
END ClassDelete;
PROCEDURE ClassFind(
ID_C in Class.Class_id%Type ,
C_Type out Class.Tybe%Type ,
C_Name out Class.Class_name%Type ,
C_Max out Class.Max%Type )
IS
BEGIN
SELECT Tybe, Class_name, Max
INTO C_Type, C_Name, C_Max
FROM Class
WHERE Class_id = ID_C;
END ClassFind;
FUNCTION Find(
ID_C in Class.Class_id%Type ,
C_Type out Class.Tybe%Type ,
C_Name out Class.Class_name%Type ,
C_Max out Class.Max%Type
) RETURN BOOLEAN
IS
BEGIN
SELECT Tybe, Class_name, Max
INTO C_Type, C_Name, C_Max
FROM Class
WHERE Class_id = ID_C;
RETURN TRUE;
Exception
WHEN NO_DATA_FOUND THEN
RETURN False;
END Find;
FUNCTION FindClass(
ID_C in Class.Class_id%Type
) RETURN Class%ROWTYPE
IS
RECORD_C Class%ROWTYPE;
BEGIN
SELECT *
Into RECORD_C
From Class
Where ID_C=Class_id;
RETURN RECORD_C;
END FindClass;
END PKG_Class;

Answer 1

In the body of procedure ClassUpdate, you update the values in the columns of table Class. In the update statement, you update the column C_Max to the value Max. That's the wrong way. The name of the column in the table is Max, and you want to update it to the value passed as an argument, C_Max. An assignment is one-directional: the right-hand side is assigned to the left-hand side. You can't turn around the "equality" since it's not really an equality, it only uses the same symbol.
If I am reading the rest of your code correctly, you are making similar mistakes for the other columns.
As an aside, max is the name of an aggregate function. While it is not reserved (which means you may use it as a column name), you still shouldn't use it as a column name; you will create confusion for yourself and for others who may need to maintain your code. And even if this is just for school (meaning, no one will ever maintain this code), it is best to form good habits.